public class Rour {
    public static void main(String[] args) {
        Animal animal = new Dog();
        animal.shout();
        ((Dog) animal).run();
    }
  }
class Animal {
    void shout() {
        System.out.println("animal shout！");
    }
  }
class Dog extends Animal {
    void shout() {
        super.shout();
        System.out.println("wangwang……");
    }
    void run() {
        System.out.println("Dog is running");
    }
  }
